Chipping cutter construction



July 6, 1954 w. o. FORMAN 2,682,996

CHIPPING CUTTER CONSTRUCTION Filed Jan. 25, 1951 INVENTOR.

WILL/ 1y O FEE/MAN Mfi * ATTo/EWEY Patented July 6, 1954 UNITED STATES PATENT OFFICE CHIPPING CUTTER CONSTRUCTION William '0. Forman, Fitchburg, Mass., assignor to Fitchburg Engineering Corporation, Fitchburg, Mass, a corporation of Massachusetts Application January 25, 1951, Serial No. 207,689

. Claims. 1

This invention relates to chipping machines and cutter constructions therefor principally for chipping and comminuting logs, brush, tree trimmings, twigs, etc., for the purpose of reducing the bulk to an easily handled minimum and also for converting the material into wood pulp, animal bedding, and the like.

The principal object of the present invention resides in the provision of a novel combination of a rotary cutter, a stationary bed knife cooperating therewith, and a feed plate in conjunction with the bed knife arranged in a novel manner relative thereto for achieving an improved result for faster feeding and smoother and cleaner cutting particularly of the smaller parts such as smooth twigs, and also making the cutter last longer than has been possible heretofore, without resharpening.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings in which Fig. 1 is a vertical sectional view through the cutter, bed knife, and a portion of the feeding plate;

Fig. 2 is a view similar to Fig. 1 but illustrating one of the limits of movement of the feeding plate;

Fig. 3 is a view on an enlarged scale illustrating the cooperation between the three elements; and

Fig. 4 is a perspective view of the bed knife, broken away.

Referring now to Fig. 1, the frame of the machine is generally indicated at It! and it includes a hopper I2 which in this case is generally located for the work to be inserted in the direction of the arrow l4 more or less horizontally to be supported by a feed plate generally indicated at 16. A rotary cutter is illustrated at l8 and this cutter has been described in detail in my copending application Serial No. 107,689, filed July 30, 1949. This cutter comprises in general a series of inserted planer type cutting bits 20 which may be adjusted, reground, reset, etc., and each being located by a wedge type clamp 22 in a gullet 24. These gullets have the forward corners thereof removed as at 26 for a purpose to be described.

The frame I0 also includes a bed knife supporting member 28 having a slot 39 to accommodate an adjusting bolt 32 threaded into the bed knife 34 which is tightly clamped to the face of the knife support 28 as will be clear, in vertically adjusted position. The knife support 28 is preferably located on a slight inclination 2 to the vertical and is offset a small amount from a vertical plane through the axis of the cutter IS, in the direction of motion of the work and rotation of the cutter head.

The feed plate 16 comprises a generally pivoted plate having an upturned end 36, this plate being pivoted at 38 and capable of sliding in a slot 40 so that the forward edge of the plate which comprises a relatively sharp nose 42, may be depressed to slide along the inclined forward surface 44 of the bed knife 34. A through rod 46 extending into end slots 48 forms an anchor for the springs 50 which cause the feed plate to be held against the bed knife.

The feeding plate is normally held upwardly and forwardly in the Fig. 1 position by the relatively powerful springs 50, clearly shown in my co-pending application referred to, and a threaded bolt 5'2 which is adjustable, limits the upward movement of the feed plate by contact with the rod 46.

The bed knife 34 is beveled off along its edges as at 54, on an angle at substantially When the bottom plate I6 is in its uppermost position as in Figs. 1 and 3, the nose 42 runs smoothly into the surface 54 and the latter in effect forms a continuation of the former. In practice the bed knife is set to clear the cutting edges of the blades 20 by only three thousandths to five thousandths of an inch. That is, the point 56, see Fig. 3, is spaced from the cutting edges of the cutter 20 the amount stated. The feed plate, of course, is not fixed, but moves downwardly against the action of the springs when heavy material is thrust into the hopper and rests thereon, while the heavy material is acted upon by the cutter 29 which operates at extremely high speeds. A log for instance will come to rest against the bed knife on surface 44 thereof while the feed plate gradually moves the log up into the rotating cutters. These cutters clearly will break up all chips into small pieces in cooperation with the point 56 of the bed knife.

It is necessary to set the end of the feed plate 42 by means of the bolts 52 at a distance from the cutter blades greater than five thousandths of an inch because when the feed plate is set as close as five thousandths of an inch it manages to get in contact with the cutter blades and rapidly dulls them. Of course, the bed knife being fixed cannot have this effect, but the movement of the feeding plate causes engagement thereof with the cutter blades regardless of the stopping means 52.

If the bed knife corners 54 were not ground off, it would be impossible to set the bed knife as close to the cutter edges as described because a sharp corner would be presented by the bed knife to the cutter edges. With the bevels 54 however, arranged as shown, the points at 58 are located farther away from the cutters than the points 56 and this, therefore, provides a slanting surface'up which the cutter edges in effect travel. It is believed it is because the edgesEBare located in the manner described, closer to the cutters 20 than the leading edges 58, that the ability of providing the above described close adjustment is achieved.

By reason of the bevels 54 onthe bed knife it is possible to set the feed plate to 'of an inch away from the edges of the cutter blades :and still have a smooth uninterrupted surface over which the material flows while it is'being chipped, and the absence of the relatively sharp corner of the bed knife 34 does away with a ledge or interruption which otherwise tends to hold back theforward feeding movement of them-aterial.

When cutting brush or tree trimmings, there are always relatively large amountsof smooth .-twigs,--which are apt to get through the machine without being cut up, but by means of the new :b'evel edge 5%, resulting in the close adjustment described, even the smoothest twigs are out clean off instead of coming out in strings which may .havebeen stripped by the blades, but not cut off.

This invention provides for faster operation, cleaner cutting, particularly of smooth twigs, :etc and'makes the machine capable of producing fine chips for cattle bedding, chicken litter, and similar uses "without however slowing down the action but instead actually increasing it.

Having thus described my invention and the advantages thereof, 1 do not wish to be limited to the details herein disclosed otherwise than aszse't "forth in the claims, but what I claim is:

1. A self-feeding wood and brush chippingmachine comprising-a frame, materialc'omminuting "means including a cylindrical cutter head rotatably mounted on said frame and a stationary blade extending toward and coacting with the rotatable cutter head, work feeding 'and supporting means coacting with the 'comminutin'g 2. The machine of claim 1 wherein the table end portion and the bevel on the stationary knife edge are substantially smooth and continuous in the said extreme close position thereof to the cutter head.

3. The machine of claim 1 wherein the table end portion and the bevel on the stationary knife edge are substantially -smo'othand contmuous in the said 'extreme close :position thereof to the cutter head, said bevel and table end portion beiing located on a slant toward the cutter head from the main portion of the table.

4. The machine of claim 1 wherein opposite edges'ofthe stationary knife are beveled.

5. h'self-feeding wood and brush chipping machine comprising-a frame, material comminuting means includingra cylindrical cutter head, rotatably mounted on an axis on said frame and a stationary blade extending toward and coacting with the rotatable cutter head, peripherally spaced longitudinal knives on the cutter head, work feeding and supporting means coacting with said :comminuting means for automatically feeding =th'erethrough material of varying'size independent of gravity, 1 said feeding and supporting means comprising a-table-pivoted onan-axis parallel to the cutter head axis and arranged in generally ta-ngential-relation'to the "cutter head, the f-r'eeend of said table lying adjacent said cutter head and said blade, supporting means for the free end of the table providing yielding movement of said table end toward and away from the rotatable cutter head, means urgingthe "table toward the cutter head while its end is maintained in sliding relation against the sta- -.tionary-blade, andmeans limiting the-movement terminating in an .edgeset closer to the .knives than the free end of the tablaat' theclosest approach thereof 'to the knives.

References Cited in the file of this patent UNI'IED STATES PATENTS Number Name Date 443,522 Hughes Dec. 30, '1890 1,348,471 Aspinwall Aug. 3, 1920 1,464,690 Andrews "Aug. 14, 1923 1,858,527 Simmons "May '17, 1932 2,045,386 Gottschalk June 23, 1936 2,557,897 Sullivan June 19, 1951 2,634,062 Forman- Apr. 7, I953 FOREIGN PATENTS Number Country Date 461,764 Great Britain Feb. 2-4, 1937 

